\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{circuitikz}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\ctikzset{bipoles/length=1cm}
\begin{document}
\small
\begin{circuitikz}[>=latex, scale=0.8,european]
  % \useasboundingbox(0.9,0)rectangle(5.1,5);
  \draw (0,0) -- (5,0) to [R=$R_1$] (5,4)--(0,4);
  \draw (3,0) to [R=$R_2$, *-*] (3,4);
  \draw [->] (.5,4)--(1.5,4)node [above]{3A};
  \node at (6.2, 2.4) { \qty{5}{mA}};
  \node at (6.2, 1.6) {\qty{100}{\ohm}};
  \draw [fill=white](0,4) circle (2pt);
  \draw [fill=white](0,0) circle (2pt);
\end{circuitikz}
\end{document}